Continuity mistake: When anybody dives into the lake, their wetsuits are black. But in the water, they are grey.
Plot hole: Doctor Yes' execution trap involves a booth flooding with water, drowning the occupant, and the water pushes a float upwards, eliminating another via a spinning blade. However, several times the float reaches the top of the booth, and the spinning blade doesn't kill anyone. There's also a breathing space at the top of the booth, so people couldn't drown in there.